JP4452779B2 - Film-forming material and method for producing metal material - Google Patents

Description

The present invention relates to a magnesium compound Mg ₂ X (X is an element selected from the group consisting of Si, Ge, Sn, and Pb, and combinations thereof, which are excellent in hardness, rigidity, corrosion resistance, and wear resistance. The same applies if not described), the compound coating, a metal material having the compound coating, and a method for producing them.

It is also described in the equilibrium diagram that each element X of Si, Ge, Sn, or Pb belonging to Group 4B of the periodic table forms a compound of magnesium (Mg) and Mg ₂ X. Regarding its characteristics, for example, regarding Mg ₂ Si, as described in JP-A-6-81068 and JP-A-2000-17352, it has excellent corrosion resistance. There is an application for dispersing as corrosion-resistant particles in a surface coating. However, there is no disclosure so far regarding the use of Mg ₂ Si alone as Mg ₂ X alone.
As a means for imparting corrosion resistance to a metal material, conventionally, an organic film or an inorganic film is generally formed, and there are various methods such as painting, plating, or surface modification. However, these methods have problems such that a sufficient hardness cannot be obtained for the coating, and it is difficult to coat a relatively thick region.
Regarding the method for producing Mg ₂ X, when Mg powder is used, a stable oxide film (MgO) is present on the powder surface, which inhibits reaction and diffusion in the solid phase with the powder composed of element X. Therefore, conventionally, the element X powder is first solidified, and the magnesium compound Mg ₂ X is synthesized by advancing a liquid phase reaction between Mg and element X by a method of impregnating and infiltrating Mg in that state.
Further, as the method for producing a Mg ₂ X, there is a mechanical alloying method. According to this method, since the starting material to be used is in the form of a powder, the oxygen content increases particularly in the case of Mg powder. As a result, various properties, particularly corrosion resistance, are reduced by the high amount of oxygen in the obtained Mg ₂ X. In addition, since the sample obtained after mechanical alloying is in a powder state, there is a problem in characteristics such as oxidation when taken out, and there is a risk of explosion, and the solid phase synthesis process of the magnesium compound Mg ₂ X It was not suitable for.
Under such circumstances, the present inventor managed mixed raw materials in Japanese Patent Application No. 2001-292117 (filed on September 25, 2001) and Japanese Patent Application No. 2001-292118 (filed on September 25, 2001). Mg ₂ Si particle-dispersed magnesium in which fine Mg ₂ Si is generated and dispersed in the matrix by the reaction of Mg and Si by heating / holding in an appropriate solid phase temperature range below the melting point of Mg in a heated atmosphere A composite material and its manufacturing method were proposed.
By the way, in order to obtain Mg ₂ X having improved hardness / rigidity, wear resistance, and / or corrosion resistance, it has been known that Mg ₂ X having fine grains may be synthesized.
However, it has been difficult to produce an Mg ₂ X compound having a fine particle diameter of less than about 10 μm by the conventional technique. The reason is as follows. That is, the case where fine Si particles are obtained by pulverization or the like is considered when using the conventional powder manufacturing technique. Even if fine Si particles smaller than 1 μm are produced, Si particles aggregate due to electrostatic attraction based on an increase in the surface area of the Si particles, and a coarse lump of about 10 to several tens μm is formed. Even if it is mixed with Mg powder in such a state and pressed and heated, the particle diameter of the obtained magnesium compound Mg ₂ Si exceeds 10 μm depending on the particle diameter of the Si particles. Therefore, improvement of hardness, abrasion resistance, and / or corrosion resistance was not expected. In the above description, only Si has been mentioned for the sake of simplicity, but such a problem is not limited to Si but also occurs in a metal powder such as Ge, Sn, and Pb.
From such a point, it has been difficult to produce an Mg ₂ X (X: Si, Ge, Sn, Pb) compound having a fine particle diameter of less than about 10 μm by the conventional technique.

An object of the present invention is to provide Mg ₂ X having fine grains.
Another object of the present invention is to provide Mg ₂ X having improved hardness, stiffness, wear resistance, and / or corrosion resistance.
Still another object of the present invention is to provide a magnesium compound film having the above-mentioned characteristics.
Still another object of the present invention is to provide a film forming material capable of forming the above film.
Still another object of the present invention is to provide a magnesium alloy material having a magnesium compound film having the above characteristics formed on the surface thereof.
Still another object of the present invention is to provide a metal material having a magnesium compound film having the above characteristics formed on the surface thereof.
Still another object of the present invention is to provide a method for producing Mg ₂ X having the above characteristics.
Still another object of the present invention is to provide a method for producing a magnesium alloy material having the above characteristics.
Still another object of the present invention is to provide a method for producing a metal material having the above characteristics.
The present inventors have found a method for synthesizing Mg ₂ X particles by solid phase reaction. In particular, the present inventors have found that there is no significant grain growth (grain coarsening phenomenon) in the synthesis process. The size of the synthesized are Mg 2 _X particles were found to be approximately equal to the particle diameter of X powder which is the starting material.
Mg ₂ X according to the present invention is a compound of an element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg), and is 10 nanometers (nm) or more and 10 microns (μm). It has the following particle size (crystal particle size).
The number of the compound Mg ₂ X may be one, but it should be at least one, such as a combination of two, three, etc. Further, it is preferable that the magnesium alloy material or metal material coated with the compound Mg ₂ X (formed with a film) does not cause corrosion even when subjected to a salt spray test defined in JIS Z 2371 for 100 hours.
Compound Mg ₂ X has (1) a particle size of 10 nanometers (nm) or more and 10 microns (μm) or less, preferably 10 to 500 nm, more preferably 30 to 250 nm, and (2) 10 nanometers ( nm) to 500 nanometers (nm), preferably 300 nm or less, more preferably 30 to 250 nm, (3) 300 nanometers (nm) to 10 microns (μm), preferably One having a particle diameter of 500 nm or more (for example, 500 nm to 5 μm), more preferably 1 to 3 μm, (4) a first particle diameter range of 10 nanometers (nm) to 300 nanometers (nm) and 300 nanometers ( nm) to 10 microns (μm), and those containing particles in both particle size ranges.
Further, each Mg ₂ X should have a hardness of 130 or more by a Vickers hardness tester using a load of 50 g. At this time, Mg ₂ X in which X is Si has a hardness of 300 or more, preferably 300 to 450, more preferably 350 to 450 in a Vickers hardness meter using a load of 50 g. In particular, when the particle diameter of Mg ₂ X is 10 to 300 nm, the hardness is preferably 330 to 450 with a Vickers hardness meter using a load of 50 g.
Mg ₂ X, in which X is Ge, has a hardness of 230 or more, preferably 230 to 400, more preferably 330 to 400 in a Vickers hardness meter using a load of 50 g. In particular, the particle diameter of Mg ₂ X is 10 to 300 nm, and the hardness is preferably 330 to 400 with a Vickers hardness meter using a load of 50 g.
Mg ₂ X in which X is Sn has a hardness of 130 or more, preferably 130 to 250, and more preferably 160 to 250 in a Vickers hardness meter using a load of 50 g. In particular, it is preferable that the particle diameter of Mg ₂ X is 10 to 300 nm and the hardness is 160 to 250 with a Vickers hardness tester using a load of 50 g.
Mg ₂ X in which X is Pb is a Vickers hardness meter using a load of 50 g, and has a hardness of 160 or more, preferably 160 to 270, more preferably 190 to 270. In particular, the particle diameter of Mg ₂ X is 10 to 300 nm, and the hardness is 190 to 270 with a Vickers hardness meter using a load of 50 g.
The magnesium compound coating according to the present invention is mainly composed of a compound Mg ₂ X of an element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg). Preferably, the particle size of Mg ₂ X is 10 nanometers (nm) or more and 10 microns (μm) or less.
The film forming material according to the present invention is mainly composed of a compound Mg ₂ X of an element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg).
The magnesium alloy material according to the present invention includes a magnesium alloy base material and a magnesium compound coating formed on the magnesium alloy base material. The magnesium compound coating is composed mainly of a compound Mg ₂ X of an element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg). Preferably, the magnesium alloy material does not cause corrosion even when subjected to a salt spray test specified in JIS Z2371 for 100 hours.
The metal material according to the present invention has a coating containing as a main component at least one of a compound Mg ₂ X of element X and magnesium selected from the group consisting of Si, Ge, Sn and Pb. Preferably, the metal material does not cause corrosion even when subjected to a neutral salt spray test specified in JIS Z 2371 for 100 hours.
The manufacturing method of Mg ₂ X according to the present invention includes a first sample of an element X selected from the group consisting of Si, Ge, Sn, and Pb and a magnesium (Mg) sample. A step of preparing the molar ratio to be 1: 2; a step of blending the first sample and the Mg sample to obtain a blend; and a plastic working step of plastically processing the blend. The plastic working process can be performed by putting the blended body in a mold die or a container.
It is preferable to further include a heating step after the plastic working step. The heating step is performed at 150 ° C. or higher and lower than 650 ° C., preferably 200 ° C. or higher and 400 ° C. or lower. At this time, the heating step is preferably performed in a vacuum or in an inert gas atmosphere. In the plastic working step, the compounded body is filled in a mold die or a container, and then the compounded body is subjected to compression deformation, extrusion deformation or backward extrusion, and any combination thereof, and each sample of the compound is mixed and It is preferable to perform pulverization and / or alloying reaction, and it is preferable that part or all of the first sample and the Mg sample are made of Mg ₂ X.
The plastic working step is a set of a first step in which the compounded body is compressed and solidified to obtain a compression-solidified intermediate, and a second step in which the compression-solidified intermediate is extruded backward to obtain a rear extrusion molded body. This step may be repeated once or a plurality of times, and may be performed by a step of compressing and solidifying the backward extruded product obtained thereby.
The manufacturing method of the magnesium alloy material according to the present invention includes a step of forming a magnesium compound film on the surface of the magnesium alloy substrate. The magnesium compound coating is composed mainly of a compound Mg ₂ X of an element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg).
The magnesium compound film forming step includes, for example, coating the surface of the magnesium alloy substrate with the compound Mg ₂ X by a sputtering method. As one example, the sputtering is performed by using a film forming material mainly containing the compound Mg ₂ X as a target material. In this case, more specifically, the magnesium compound film forming step is performed by depositing a target material mainly composed of the compound Mg ₂ X on the surface of the magnesium alloy substrate by an ion beam sputtering method. As the target material, a material obtained by alternately bonding a magnesium plate and a plate made of the element X can be used.
As another example, the magnesium compound film forming step is performed by a step of applying pressure and / or heating after depositing Mg ₂ X on the surface of the magnesium alloy substrate. As yet another example, the magnesium compound film forming step includes coating the surface of the magnesium alloy substrate with the compound Mg ₂ X by a thermal spraying method. Yet another example includes coating the surface of the magnesium alloy substrate with the compound Mg ₂ X by glow discharge sputtering. As yet another example, the magnesium compound film forming step includes coating the surface of the magnesium alloy substrate with the compound Mg ₂ X by a coating method.
A method for producing a metal material according to the present invention includes a step of coating a surface of a metal material with a compound Mg ₂ X of an element X selected from the group consisting of Si, Ge, Sn, and Pb and magnesium (Mg), and coating Forming a film mainly composed of the compound Mg ₂ X on the metal material by pressurizing and heating the layer or performing one of pressurization and heating.
As one example, the coating step includes coating the surface of the metal material with the compound Mg ₂ X by a thermal spraying method. As another example, the coating step includes coating the surface of the metal material with the compound Mg ₂ X by ion beam sputtering. As yet another example, the coating step includes coating the surface of the metal material with the compound Mg ₂ X by a coating method. As yet another example, the coating step includes coating the surface of the metal material with the compound Mg ₂ X by glow discharge sputtering.
The metal material may be either ferrous or non-ferrous, and the former includes steel materials such as carbon steel and stainless steel, steel materials such as tool steel and free-cutting steel, cast iron materials such as ductile cast iron and gray cast iron, stainless steel Cast steel materials such as cast steel and carbon steel cast steel, and the latter include magnesium alloy, aluminum alloy, titanium alloy, copper alloy, zinc alloy, lead alloy, lithium alloy and the like.
Mg 2 _X, such as Mg 2 _Si is formed on the powder sintered body by heating and pressing the Mg and X, as long as possible manufacturing, can be adopted various methods. For example, it is manufactured by a method such as BMA (bulk mechanical alloying), ECAP (shear processing), HPT (high pressure torsion), CEC (repetitive extrusion upsetting). Further, the Mg ₂ X powder is manufactured by pulverization using, for example, a stamp mill, a ball mill or the like. At this time, the particle diameter of the powder is preferably fine from the viewpoint that a good coating characteristic surface such as a uniform coating layer can be easily obtained, for example, 100 μm or less, more preferably 10 μm or less. .
In order to coat this Mg ₂ X powder on the surface of a metal material (form a coating), bonding, adhesion, or coating by thermal spraying, electrodeposition coating, ion beam sputtering, etc. To thick film. The degree of coating (area) may be appropriately set as the entire surface or only the necessary portion depending on the application.
For example, a film formed by bonding and adhesion may be formed by applying Mg ₂ X to the surface of the metal material in a layer having a required thickness, and then pressing or heating, or pressing and heating. it can.
Examples of the coating by thermal spraying include arc thermal spraying, gas thermal spraying, and plasma thermal spraying, and the atmosphere may be changed to an inert atmosphere under vacuum or reduced pressure as necessary. Moreover, you may use in order to improve performance, such as performing pressure forming or heat processing with respect to the coating after a thermal spraying. In this thermal spraying, it is preferable to activate the surface of the sprayed material (metal material) by blasting or the like.
Ion beam sputtering method, as a target material, the solid material used including partially solidified, or Mg 2 _X of Mg 2 _X, irradiating an ion beam to the target material is deposited on the surface of the metallic material. At this time, if unreacted components remain, it is preferable to perform post-heating of the vapor deposition surface as necessary.
Coating by painting, painted brushed with paint containing powder containing some powder or Mg 2 _X of Mg 2 _X, spraying, dip coating, powder coating, such as by electrodeposition coating on the surface of the metallic material, If necessary, curing treatment such as preheating and post-heating is performed. If necessary, a synthetic resin such as an epoxy resin or an inorganic material such as silicate or water glass is used as a spreading agent. Further, various pigments and additives may be mixed.
As for the use of the Mg ₂ X-coated (with coating) metal material thus manufactured, iron-based structures, pipes, mechanical parts, etc., non-ferrous-based structural parts, home appliance parts, mechanical parts, etc. Assistive care equipment, sports parts, hobby supplies, etc.

FIG. 1 is a flowchart showing a method for producing the compound Mg ₂ X of the present invention.
FIG. 2 is a diagram schematically showing one embodiment of a strong plastic working step which is one step of the method for producing the compound Mg ₂ X of the present invention.
FIG. 3 is a diagram showing an embodiment for producing a metal material having an Mg ₂ X coating.
FIG. 4 is a diagram for explaining a gas spraying method which is an embodiment for producing another metal material.
FIG. 5 is a diagram for explaining an ion beam sputtering method which is an embodiment for producing another metal material.
FIG. 6 is a diagram showing the results of X-ray diffraction (XRD) of solidified product A-8 (a) of Example 2 and its starting material (b).
FIG. 7 is a diagram showing a TEM observation result of the solidified body A-8 of Example 2.
FIG. 8 is a diagram showing a TEM observation result of solidified body A-7 of Example 2.
FIG. 9 is a diagram showing a TEM observation result of the solidified body A-9 of Example 3.
FIG. 10 is a diagram showing a TEM observation result of the final product A-9 ′ obtained in Example 3.
FIG. 11 is an X-ray diffraction diagram of Example 4.
FIG. 12 is a cross-sectional view of the fourth embodiment.

次に、この発明の化合物Ｍｇ_２Ｘの製造方法を図１のフローを用いて説明する。
出発原料として、純Ｍｇと元素Ｘを用いる。純Ｍｇは、粉末状、チップ状又は塊状素材を用いることができる。また、元素Ｘは、Ｓｉ、Ｇｅ、Ｓｎ及びＰｂから選ばれる１種類であり、粉末状、チップ状又は塊状素材を用いることができる。モル比でＭｇ：Ｘ＝２：１となるように各出発原料を秤量し、両者を配合・混合する。このとき、Ｘとして２以上の元素を用いてもよい。
この配合・混合体に対して繰返し塑性加工を施す。これにより、その加工過程でＭｇと元素Ｘとが固相反応することによって粒子径３００〜５００ｎｍ以下のマグネシウム化合物Ｍｇ_２Ｘが合成される。したがって、後述する加熱処理工程を有することなく、塑性加工工程により、Ｍｇ_２Ｘが合成される。このとき、Ｘが２種以上であれば、２種以上のＭｇ_２Ｘが合成される。
塑性加工工程の際、出発原料がすべてマグネシウム化合物Ｍｇ_２Ｘへと合成される場合、そのＭｇ_２Ｘの粒子径は、上記範囲、即ち１０〜５００ｎｍ以下である。
一方、出発原料がすべてＭｇ_２Ｘに合成されることなく、未反応のＭｇと元素Ｘが残存する場合がある。この場合、元素Ｘの粒子径は３００ｎｍ〜１０μｍ程度である。未反応のＭｇと元素Ｘとは、さらに加熱処理を行うことにより、Ｍｇ_２Ｘへの合成をすることができる。この際に得られるＭｇ_２Ｘの粒子径は、未反応のＸ粉末の粒子径と同等の３００ｎｍ〜１０μｍ、例えば５００ｎｍ〜１０μｍとなる。最終的に得られるＭｇ_２Ｘの粒子径は、塑性加工工程によって得られる１０〜５００ｎｍのものと、熱処理工程によって得られる３００ｎｍ〜１０μｍ（例えば５００ｎｍ〜１０μｍ）との双方が存在する。
上記塑性加工工程は、種々の手段によって行うことができる。その一例を、図２を参照しつつ、以下に説明する。
図２の（ａ）は、金型臼１と下パンチ３とで形成された器に出発原料の配合・混合体５を充填した模式図である。
次いで、配合・混合体は、塑性加工工程（ｂ）〜（ｆ）に付される。塑性加工工程（ｂ）〜（ｆ）は、圧縮用上パンチ７と押込用上パンチ９とを備えるプレス加工機で行われる。なお、ここで用いるプレス加工機として既存の油圧式、機械式、スクリュー式など、いずれの駆動方式のプレス機であっても使用することができる。
工程（ｂ）は、圧縮用上パンチ７を金型臼内に下降させて、配合・混合体が圧縮・固化される。次いで、圧縮用上パンチ７を上昇させた（工程（ｃ））後、工程（ｄ）では、押込用上パンチ９を金型臼１内に下降させる。この際、工程（ｄ）の図に示すように、圧縮固化した配合・混合体（固化体）が後方（矢印Ｂの方向）に押出されることによって塑性加工が付与され、Ｍｇ及び元素Ｘが機械的に粉砕されて微細化する。
次に、押込用上パンチ９を上昇させた（工程（ｅ））後、再度、圧縮用上パンチ７を金型臼１内に下降させて図２（ｆ）においてＵ字型となっている固化体を圧縮する。これにより、金型臼１内面に沿って存在する固化体が金型臼１内側（矢印Ｃの方向）に回りこむ。これら一連の作業（ｂ）〜（ｆ）により、配合・混合体は、より混合・攪拌され且つ各出発原料は微細化される。
一連の作業（ｂ）〜（ｆ）、即ち圧縮過程（圧縮用上パンチ７による加圧・圧縮加工）と押込用上パンチ９による後方押出塑性加工とを１サイクルとして、所定のサイクル数を繰返すことにより、Ｍｇ及びＸの均一混合及び微細化を経て、固相拡散現象によってＭｇ_２Ｘが合成される。
この加工において、出発原料の配合・混合体に与える塑性加工量を制御することにより、Ｍｇ_２Ｘの粒子径を１０〜５００ｎｍの範囲で調整することができる。また、その塑性加工量は、種々のパラメータを変化することによって、制御することができる。例えば、パラメータとして、（ｂ）〜（ｆ）のサイクル数、（ｄ）の押込用上パンチ９の荷重及び速度、金型臼１の内径と押込用上パンチ９の外径との関係、（ｆ）の圧縮用上パンチ７の荷重及び速度などを挙げることができる。
なお、金型臼１の底部での配合・混合体が停滞することを解消するため、必要に応じて、あるサイクル数間隔で金型臼１を上下反転させるか、又は配合・混合体を取り出した後に該配合・混合体を上下反転して再度圧縮・後方押出加工を施す、などの方法を行うことも有効である。
作業（ｂ）〜（ｆ）を所定のサイクル繰り返した後に、作業（ｂ）を行うことで、円筒状の固化体（図２（ｇ））を得ることができる。固化体は、上述のように、ＭｇとＸとがすべて反応している場合、粒子径１０〜５００ｎｍのＭｇ_２Ｘのみからなり、すべて反応していない場合、上記範囲の粒子径を有するＭｇ_２Ｘ、並びに未反応Ｍｇ及びＸからなる。
塑性加工工程後に、加熱処理工程を有する場合、その加熱温度は、１５０℃以上６５０℃未満、好ましくは２００℃以上４００℃以下であるのがよい。Ｍｇの融点である６５０℃を越えると、Ｍｇの液相が出現し、元素Ｘと反応して得られるＭｇ_２Ｘの粒子径が粗大化する傾向が生じる。また、１５０℃未満であると、ＭｇとＸとの間で十分に反応が進行せず、加熱処理後であっても未反応のＭｇおよびＸが残存するため、好ましくない。特に、加熱処理によって微細粒を有するＭｇ_２Ｘを得るには、加熱温度が２００℃以上４００℃以下であるのがよい。なお、試料の酸化抑制の観点から加熱雰囲気は、真空下又は不活性ガス下とすることが望ましい。
＜Ｍｇ_２Ｘ被膜を有する金属材料とその製造方法＞
Ｍｇ_２Ｘ被膜を有する金属材料は、基材となる金属材料の表面にＭｇ_２Ｘ被膜を有してなる。「表面」は、Ｍｇ_２Ｘ被膜を有する金属材料の用途などに依存するが、金属材料の全表面であっても一部であってもよい。金属材料は、マグネシウム合金材料であってもよいし、それ以外の金属または合金材料であってもよい。
マグネシウム合金は、マグネシウムを主要成分として含む合金であれば、いずれのものを用いてもよい。例えば、ＡＺ３１合金、ＡＭ６０合金、ＡＺ９１合金、ＺＫ６０合金、ＺＭ２０合金などが挙げられる。
以下の方法により、金属材料の表面にＭｇ_２Ｘ被膜を設けることができる。即ち、基材である金属材料と、上述のＭｇ_２Ｘの固化体又はＭｇ_２Ｘを一部に含む固化体とを準備する工程；及び金属材料の表面に固化体の層を、従来より公知の方法を用いて設ける工程；並びに、必要ならば、固化体中の未反応のＭｇ及びＸを反応させるために加熱する工程；及び／又は、固化体の層と基材である金属材料との密着性を高める工程を有することにより、Ｍｇ_２Ｘ被膜を有する金属材料を得ることができる。
なお、ここで「Ｍｇ_２Ｘの固化体」とは、上述のＭｇ_２Ｘの製造方法で、すべてのＭｇとＸとが反応して得られた固化体を示し、「Ｍｇ_２Ｘを一部に含む固化体」とは、ＭｇとＸとの一部が反応してＭｇ_２Ｘとなり一部が未反応のＭｇ及びＸが残存する状態の固化体、例えば図２（ｇ）に示すものをいう。
また、必要ならば有してもよい工程である「固化体中の未反応のＭｇ及びＸを反応させるために加熱する工程」における加熱温度は、１５０℃以上６５０℃未満、好ましくは２００℃以上４００℃以下であるのがよい。前述したように、Ｍｇの融点である６５０℃を越えると、Ｍｇの液相が出現し、元素Ｘと反応して得られるＭｇ_２Ｘの粒子径が粗大化する傾向が生じる。また、１５０℃未満であれば、ＭｇとＸとの間で十分に反応が進行せず、熱処理後であっても未反応のＭｇおよびＸが残存するため、好ましくない。特に、微細粒のＭｇ_２Ｘを創製するためには、加熱温度は２００℃以上４００℃以下がより好ましい。なお、試料の酸化抑制の観点から加熱雰囲気は、真空下又は不活性ガス下とすることが望ましい。
金属材料の表面に固化体の層を設ける工程について、図面を参照しつつ、より具体的に説明する。
図３は、金型１１内に挿入した金属材料１３の表面に固化体１５を配置し、その後、加熱及び／又は加圧するこにより、固化体と金属材料とを接合させる工程及びそれによって得られる「Ｍｇ_２Ｘ被膜１９を有する金属材料１７」を示している。この方法を用いた場合、得られるＭｇ_２Ｘ被膜の厚さは、用いる固化体の厚さにほぼ依存し、一般的には数ｍｍ程度の厚さとなる傾向にある。
他の方法として、溶射法を適用することができる。具体的には、アーク溶射、プラズマ溶射、ガス溶射、ＨＶＯＦ（Ｈｉｇｈ Ｖｅｌｏｃｉｔｙ Ｏｘｙｇｅｎ Ｆｕｅｌ）法などが挙げられる。図４は、一例としてガス溶射を示している。この方法は、金属材料１３に、溶射ガン２０からアセチレンガスと酸素ガスとの混合ガスを燃焼させたガス炎２０ａを吐出させ、そのガス炎２０ａにＭｇ_２Ｘ粉末１５ａを送り込んで、そのＭｇ_２Ｘ粉末を金属材料１３の表面に溶射してＭｇ_２Ｘ被膜１９を形成する。
また、別の方法として、図５に示すイオンビームスパッタリング法を適用することもできる。この図５において、ターゲット材２１として上述のＭｇ_２Ｘ固化体又はＭｇ_２Ｘを一部に含む固化体を用いることができる。イオンビームをターゲット材２１に照射することにより、Ｍｇ_２Ｘを被膜１９として金属材料１３の表面に蒸着・形成することができる。
なお、固化体として、Ｍｇ_２Ｘを一部に含む固化体を用いた場合、固化体中の未反応Ｍｇ及び未反応Ｘが気相中又はターゲット材上などで反応してＭｇ_２Ｘを形成し、該Ｍｇ_２Ｘを被膜として金属材料表面に蒸着・形成することができる。また、未反応Ｍｇ及び未反応Ｘがそのまま金属材料表面に蒸着・形成される場合もある。後者の場合、未反応Ｍｇ及び未反応Ｘを反応させるため、蒸着形成した層をさらに加熱工程に付するのがよい。加熱工程の加熱温度は、上述の温度、即ち１５０℃以上６５０℃未満、好ましくは２００℃以上４００℃以下であるのがよい。
このようにして得られた化合物Ｍｇ_２Ｘは、ナノスケールの微細構造粒子から構成されるため、硬さ・耐摩耗性・耐腐食性に優れる。また、この化合物を被膜として金属材料表面に形成することにより、その金属材料自身の機械的特性・耐摩耗性・耐食性を向上させることができる。したがって、軽量化ニーズの高い構造用部品、例えば二輪車・自動車部品；家電部品；機械部品：パイプや棒状素材からなる介護福祉器具（車椅子・介護用ベッド・杖・福祉車両など）；スポーツ製品や釣具などのホビー用品；等の、マグネシウム合金の使用が望まれる部品・製品に本発明を適用し、硬さ・耐腐食性・耐摩耗性を大幅に向上させることができる。
以下、実施例に基づいて、この発明をさらに詳細に説明するが、この発明は本実施例に限定されるものではない。Hereinafter, the present invention will be described in detail in the order of the compound Mg ₂ X and its production method, and the metal material having the compound Mg ₂ X as a coating and its production method.
<Compound Mg ₂ X and production method thereof>
The particle diameter (crystal particle diameter) of the compound Mg ₂ X (X: Si, Ge, Sn, Pb) of the present invention is 10 nm or more and 10 μm or less. Preferably, it is 5 μm or less. As described above, Mg ₂ X obtained by the conventional method is about 10 μm at most. Further, when the particle diameter of Mg ₂ X is 10 μm or less, particularly 5 μm or less, preferably 3 μm or less, hardness and / or corrosion resistance is improved. Furthermore, the properties of Mg ₂ X are remarkably improved with the particle diameter of 300 nm to 500 nm as a boundary. Therefore, the particle diameter of the compound Mg ₂ X of the present invention is preferably 10 nm to 500 nm, or 10 nm to 300 nm. More preferably, the thickness is 30 to 250 nm.
For example, the corrosion resistance is evaluated as follows. That is, the corrosion resistance is evaluated by a salt spray test (5% saline controlled at 35 ° C.) defined in JIS Z2371. If the particle size of Mg ₂ X is not less than 10 [mu] m, whereas the corrosion start time is about 10 to 15 hours after start of the test, the particle size of Mg ₂ X is the 20 hour or so at 5 to 10 [mu] m, the 500nm~5μm In this case, when the particle size becomes 500 nm or less for the same 30 to 50 hours, it becomes 70 to 100 hours, and the corrosion resistance improves as the particle size decreases.
In addition, the hardness is evaluated as follows. That is, as described in Table 1, the hardness of Mg ₂ X (micro Vickers hardness; imparting a load of 50 g) causes a remarkable increase in hardness when it reaches an ultrafine nanoparticle level below 300 nm. . In addition, even if the particle size is further reduced, for example, less than 10 nm, no further improvement in properties regarding hardness is observed. On the other hand, since the plastic processing time required for the solid phase synthesis of Mg ₂ X, which will be described later, becomes long, there is a tendency to be disadvantageous in terms of economy.

Next, a method for producing the compound Mg ₂ X of the present invention will be described using the flow of FIG.
Pure Mg and element X are used as starting materials. Pure Mg can use a powder form, a chip form, or a block material. The element X is one kind selected from Si, Ge, Sn, and Pb, and a powdery, chip-like, or massive material can be used. Each starting material is weighed so that the molar ratio is Mg: X = 2: 1, and both are blended and mixed. At this time, two or more elements may be used as X.
This compounding / mixture is repeatedly subjected to plastic working. As a result, a magnesium compound Mg ₂ X having a particle size of 300 to 500 nm or less is synthesized by a solid phase reaction between Mg and the element X in the processing process. Therefore, Mg ₂ X is synthesized by the plastic working process without having the heat treatment process described later. At this time, if X is 2 or more types, 2 or more types of Mg ₂ X are synthesized.
When all the starting materials are synthesized into the magnesium compound Mg ₂ X during the plastic working step, the particle diameter of the Mg ₂ X is in the above range, that is, 10 to 500 nm or less.
On the other hand, unreacted Mg and element X may remain without all starting materials being synthesized into Mg ₂ X. In this case, the particle diameter of the element X is about 300 nm to 10 μm. Unreacted Mg and element X can be synthesized into Mg ₂ X by further heat treatment. The particle diameter of Mg ₂ X obtained at this time is 300 nm to 10 μm, for example, 500 nm to 10 μm, which is equivalent to the particle diameter of the unreacted X powder. The particle diameter of Mg ₂ X finally obtained is both 10 to 500 nm obtained by the plastic working process and 300 nm to 10 μm (for example, 500 nm to 10 μm) obtained by the heat treatment process.
The plastic working process can be performed by various means. An example thereof will be described below with reference to FIG.
(A) of FIG. 2 is a schematic diagram in which a container formed by the mold die 1 and the lower punch 3 is filled with a blend / mixture 5 of starting materials.
Next, the blend / mixture is subjected to plastic working steps (b) to (f). The plastic working steps (b) to (f) are performed by a press machine including an upper punch 7 for compression and an upper punch 9 for pressing. In addition, as a press machine used here, it can be used even if it is the press machine of any drive systems, such as the existing hydraulic type, a mechanical type, and a screw type.
In the step (b), the upper punch 7 for compression is lowered into the mold die, and the blended / mixed product is compressed and solidified. Next, after the upper punch 7 for compression is raised (step (c)), the upper punch 9 for pushing is lowered into the die 1 in the step (d). At this time, as shown in the figure of the step (d), the compression-solidified compound / mixture (solidified body) is extruded backward (in the direction of arrow B) to give plastic working, and Mg and the element X are added. It is pulverized mechanically and refined.
Next, after the upper punch 9 for pushing is raised (step (e)), the upper punch 7 for compression is again lowered into the die 1 to form a U shape in FIG. Compress the solidified body. As a result, the solidified body existing along the inner surface of the mold die 1 wraps around the inner side of the mold die 1 (in the direction of arrow C). Through the series of operations (b) to (f), the blend / mixture is further mixed and stirred, and each starting material is refined.
A series of operations (b) to (f), that is, a compression process (pressing / compressing with the upper punch 7 for compression) and backward extrusion plastic working with the upper punch 9 for pushing are defined as one cycle, and a predetermined number of cycles is repeated. Thus, Mg ₂ X is synthesized by solid phase diffusion through uniform mixing and refinement of Mg and X.
In this processing, the particle diameter of Mg ₂ X can be adjusted in the range of 10 to 500 nm by controlling the amount of plastic processing given to the blend / mixture of starting materials. Moreover, the amount of plastic working can be controlled by changing various parameters. For example, as parameters, the number of cycles (b) to (f), the load and speed of the upper punch 9 for pressing (d), the relationship between the inner diameter of the die 1 and the outer diameter of the upper punch 9 ( The load and speed of the upper punch 7 for compression in f) can be mentioned.
In order to eliminate the stagnation of the compound / mixture at the bottom of the mold die 1, the mold die 1 is turned upside down at a certain cycle number or the compound / mixture is taken out as necessary. After that, it is also effective to perform a method such as turning the blend / mixture upside down and performing compression / backward extrusion again.
By repeating the operations (b) to (f) for a predetermined cycle and then performing the operation (b), a cylindrical solid body (FIG. 2 (g)) can be obtained. As described above, when all of Mg and X are reacted, the solidified body is composed only of Mg ₂ X having a particle diameter of 10 to 500 nm. When all of the solid bodies are not reacted, Mg ₂ having a particle diameter in the above range is used. X and unreacted Mg and X.
When it has a heat treatment process after a plastic working process, the heating temperature is 150 to 650 degreeC, Preferably it is 200 to 400 degreeC. When the melting point of Mg exceeds 650 ° C., a liquid phase of Mg appears, and the particle diameter of Mg ₂ X obtained by reacting with element X tends to increase. Further, if it is lower than 150 ° C., the reaction does not proceed sufficiently between Mg and X, and unreacted Mg and X remain even after heat treatment, which is not preferable. In particular, in order to obtain Mg ₂ X having fine particles by heat treatment, the heating temperature is preferably 200 ° C. or more and 400 ° C. or less. Note that, from the viewpoint of suppressing the oxidation of the sample, the heating atmosphere is desirably under vacuum or under an inert gas.
<Metal material having Mg ₂ X coating and method for producing the same>
Metallic material having a Mg 2 _X coating is composed with a Mg 2 _X film on the surface of the metal material as the base material. The “surface” depends on the use of the metal material having the Mg ₂ X coating, but may be the entire surface or a part of the metal material. The metal material may be a magnesium alloy material, or other metal or alloy material.
Any magnesium alloy may be used as long as it contains magnesium as a main component. For example, AZ31 alloy, AM60 alloy, AZ91 alloy, ZK60 alloy, ZM20 alloy, etc. are mentioned.
The Mg ₂ X coating can be provided on the surface of the metal material by the following method. That is, the metallic material is a substrate comprises providing a solid material comprising a portion of solid material or Mg 2 _X of the above Mg 2 _X; a layer of solid material on the surface of and metal materials, known in the prior art And a step of heating to react unreacted Mg and X in the solidified body, if necessary; and / or a layer of the solidified body and a metal material as a base material. by having a step of increasing the adhesiveness, it is possible to obtain a metal material having a Mg 2 _X film.
Here, "solid material Mg 2 _X" is a method for producing the above-mentioned Mg 2 _X, shows all of the solidified bodies and Mg and X is obtained by reacting a part of the "Mg 2 _X The “solidified body contained in” means a solidified body in which Mg and X partially react to become Mg ₂ X and partially unreacted Mg and X remain, for example, those shown in FIG. Say.
Further, the heating temperature in the “step of heating to react unreacted Mg and X in the solidified body”, which may be included if necessary, is 150 ° C. or higher and lower than 650 ° C., preferably 200 ° C. or higher. It is good that it is 400 degrees C or less. As described above, when the melting point of Mg exceeds 650 ° C., a liquid phase of Mg appears, and the particle diameter of Mg ₂ X obtained by reacting with element X tends to be coarse. Moreover, if it is less than 150 degreeC, since reaction does not fully advance between Mg and X and unreacted Mg and X remain | survive even after heat processing, it is not preferable. In particular, in order to create fine-grained Mg ₂ X, the heating temperature is more preferably 200 ° C. or higher and 400 ° C. or lower. Note that, from the viewpoint of suppressing the oxidation of the sample, the heating atmosphere is desirably under vacuum or under an inert gas.
The step of providing a solidified layer on the surface of the metal material will be described more specifically with reference to the drawings.
FIG. 3 shows a process of placing the solidified body 15 on the surface of the metal material 13 inserted into the mold 11 and then joining the solidified body and the metal material by heating and / or pressurization, and thereby obtained. “Metal material 17 having Mg ₂ X coating 19” is shown. When this method is used, the thickness of the resulting Mg ₂ X coating is almost dependent on the thickness of the solidified material to be used, and generally tends to be a thickness of several millimeters.
As another method, a thermal spraying method can be applied. Specific examples include arc spraying, plasma spraying, gas spraying, and HVOF (High Velocity Oxygen Fuel) method. FIG. 4 shows gas spraying as an example. In this method, the metal material 13, the mixed gas from the spray gun 20 and the acetylene gas and oxygen gas by discharging gas flame 20a is burned, by feeding Mg ₂ X powder 15a into the gas flame 20a, the Mg ₂ X powder is sprayed on the surface of the metal material 13 to form the Mg ₂ X coating 19.
Alternatively, an ion beam sputtering method shown in FIG. 5 can be applied. In FIG. 5, the above-described Mg ₂ X solidified body or a solidified body partially containing Mg ₂ X can be used as the target material 21. By irradiating the target material 21 with an ion beam, Mg ₂ X can be deposited and formed on the surface of the metal material 13 as a coating 19.
When a solidified body containing Mg ₂ X in part is used as the solidified body, unreacted Mg and unreacted X in the solidified body react in the gas phase or on the target material to form Mg ₂ X. The Mg ₂ X can be deposited and formed on the surface of the metal material as a coating. Further, unreacted Mg and unreacted X may be deposited and formed on the surface of the metal material as they are. In the latter case, in order to react unreacted Mg and unreacted X, the deposited layer is preferably subjected to a heating step. The heating temperature in the heating step is the above-described temperature, that is, 150 ° C. or higher and lower than 650 ° C., preferably 200 ° C. or higher and 400 ° C. or lower.
The compound Mg ₂ X thus obtained is composed of nano-scale fine structure particles, and thus has excellent hardness, wear resistance, and corrosion resistance. Further, by forming this compound as a coating on the surface of the metal material, the mechanical properties, wear resistance, and corrosion resistance of the metal material itself can be improved. Therefore, structural parts with high needs for weight reduction, such as motorcycles and automobile parts; home appliance parts; machine parts: care welfare equipment (wheelchairs, care beds, canes, welfare vehicles, etc.) made of pipes and rods; sports products and fishing gear The present invention can be applied to parts and products for which the use of magnesium alloys is desired, such as hobby articles such as, and the like, and the hardness, corrosion resistance, and wear resistance can be greatly improved.
EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to a present Example.

固化体Ａ−１〜Ａ−６は、所定回数の繰り返し強塑性加工を施すことにより、この発明が規定する粒子径、特に３００〜５００ｎｍ以下の微細な粒子径を有するＭｇ_２Ｘを固相合成できることが観察された。また、これらの固化体Ａ−１〜Ａ−６は、優れた耐腐食性およびビッカーズ硬さを有することを確認した。
一方、比較例としての固化体Ａ−１０１〜Ａ−１０４は、同一元素粉末を用いたにも関わらず、繰返し強塑性加工工程を施さず、Ｍｇ又は元素Ｘのいずれか一方の融点以上の温度域において加熱する工程を採用したため、液相反応によってＭｇ_２Ｘが合成されている。それによって得られた固化体は、Ｍｇ_２Ｘの粒子径が１０μｍを越えていることが観察された。また、これらの固化体Ａ−１０１〜Ａ−１０４は、耐腐食性およびビッカーズ硬さが著しく低い、特に固化体Ａ−１〜Ａ−６と比較すると格段に低いものであった。Pure Mg powder (average particle size: 165 μm) as a starting material, Group 4B element X as Si powder (average particle size: 23 μm), Ge powder (average particle size: 34 μm), Sn powder (average particle size: 44 μm) , Pb powder (average particle size: 29 μm) was prepared.
Each powder was weighed and mixed so that the composition molar ratio was Mg: X = 2: 1 to obtain a mixed powder body.
Each mixed powder body was subjected to a strong plastic working process at room temperature using the apparatus shown in FIG. 2 to obtain a solidified body having a cylindrical shape (35 mmφ × height about 30 mm). In the apparatus shown in FIG. 2, the inner diameter of the die (made of SKD11 steel): 35 mmφ, the outer diameter of the compression punch: 34.85 mmφ, the outer diameter of the pressing punch: 25 mmφ, and the tip radius: 12.5 mm . Pressurization with compression punch: once + pressurization with indentation punch: 1 cycle is one cycle, and the number of repetitions is 200 to 600 cycles as shown in Table 2, and solidified bodies A-1 to A-6 are produced. did.
Further, as shown in Table 2, as a comparative example, a strong plastic working step is not performed (in the table, “repetition count” is described as zero (0)), and then vacuum heat treatment is performed, and comparative solidified sample A- 101-A-104 was obtained. The heat treatment temperature was as shown in Table 2, and was heated and held at each temperature for 30 minutes.
About solidified bodies A-1 to A-6 and A-101 to A-104, the structure was observed with an optical microscope, a scanning electron microscope (SEM), and a transmission electron microscope (TEM). The particle diameter of the magnesium compound Mg ₂ X present in the solidified body was calculated by image analysis.
Further, the corrosion state of the sample surface after being subjected to a salt spray test (5% saline controlled at 35 ° C.) defined in JIS Z2371 for 100 hours was observed.
Furthermore, the hardness was measured using a Vickers hardness meter (under a load of 50 g). These results are shown in Table 2.

The solidified bodies A-1 to A-6 are subjected to solid plastic synthesis of Mg ₂ X having a particle diameter defined by the present invention, particularly a fine particle diameter of 300 to 500 nm or less, by subjecting it to repeated strong plastic processing a predetermined number of times. It was observed that it could be done. Moreover, it confirmed that these solidified bodies A-1 to A-6 have excellent corrosion resistance and Vickers hardness.
On the other hand, solidified bodies A-101 to A-104 as comparative examples were not subjected to repeated strong plastic working steps despite using the same element powder, and had a temperature equal to or higher than the melting point of either Mg or element X. Since the process of heating in the region is adopted, Mg ₂ X is synthesized by a liquid phase reaction. The solidified product thus obtained was observed to have a Mg ₂ X particle size exceeding 10 μm. In addition, these solidified bodies A-101 to A-104 have remarkably low corrosion resistance and Vickers hardness, and are particularly low compared with the solidified bodies A-1 to A-6.

Prepare pure Mg powder (average particle size: 165 μm) and Si powder (average particle size: 23 μm) as starting materials, and weigh and mix the powders so that the molar composition ratio is Mg: Si = 2: 1. A powder was obtained. The mixed powder body was subjected to a strong plastic processing step at room temperature using the apparatus shown in FIG. 2 to obtain a solidified body having a cylindrical shape (35 mmφ × height about 28 mm). In the apparatus shown in FIG. 2, the inner diameter of the die (made of SKD11 steel): 35 mmφ, the outer diameter of the compression punch: 34.85 mmφ, the outer diameter of the pressing punch: 20 mmφ, the tip radius: 10 mm, the compression punch Pressurization by 1 time + Pressurization by pressing punch: 1 cycle was defined as 1 cycle, and the number of repetitions was 300 cycles (A-7) and 600 cycles (A-8).
Only the solidified body A-7 obtained by the 300 cycle treatment step was further subjected to a vacuum heat treatment step at 350 ° C. for 30 minutes.
FIG. 6 shows the result of X-ray diffraction (XRD) performed on the solidified body A-8 obtained by the 600 cycle treatment step. For comparison, the XRD result of the starting material is also shown as (b) in FIG.
As can be seen from FIG. 6, it can be seen that the solidified body A-8 obtained by performing the 600 cycle treatment is substantially composed of a Mg ₂ Si single phase.
Moreover, the TEM observation result of solidified body A-8 is shown in FIG. 7, and the TEM observation result of solidified body A-7 after the vacuum heat treatment is shown in FIG. As can be seen from FIG. 7, it can be seen that the solidified body A-8 consists only of Mg ₂ Si fine particles of less than 100 nm. As shown in FIG. 8, repeated strong plastic working step and solidified A-7 obtained given the appropriate heat treatment step is below the 100 nm _Mg 2 Si fine particles and 500 nm _Mg 2 Si grain size of about It turns out that it consists of particles.

Prepare pure Mg powder (average particle size: 165 μm) and Si powder (average particle size: 23 μm) as starting materials, and weigh and mix the powders so that the molar composition ratio is Mg: Si = 2: 1. A powder was obtained. The mixed powder body was subjected to a strong plastic working step at room temperature using the apparatus shown in FIG. 2 to obtain a solidified body having a cylindrical shape (35 mmφ × height about 30 mm). In the apparatus shown in FIG. 2, the inner diameter of the die (made of SKD11 steel): 35 mmφ, the outer diameter of the compression punch: 34.85 mmφ, the outer diameter of the pressing punch: 20 mmφ, the tip radius: 10 mm, the compression punch Pressurization with 1 time + Pressurization with indentation punch: 1 cycle is 1 cycle, and the number of repetitions is 150 cycles to obtain a solidified body A-9, followed by vacuum heat treatment at 320 ° C. for 30 minutes. Product A-9 ′ was obtained.
FIG. 9 shows a TEM observation result of the solidified body A-9 after repeated strong plastic working, and FIG. 10 shows a TEM observation result of the A-9 ′ after vacuum heat treatment.
After repeated strong plastic working for 150 cycles, that is, in the solidified body A-9, as shown in FIG. 9A, unreacted Si particles of about 500 nm are partly present, and as shown in FIG. 9B. As described above, Mg ₂ Si having a particle diameter of about 30 to 80 nm synthesized by a solid phase reaction between Mg and Si is present. On the other hand, after vacuum heat treatment, that is, A-9 ′, Mg ₂ Si of around 500 nm exists as shown in FIG. This is almost the same as the size of the unreacted Si particles remaining after the strong plastic working, and by applying an appropriate heat treatment, the unreacted Si particles react with the unreacted Mg so that everything becomes Mg ₂ Si. And the particle diameter is considered to be the same as that of unreacted Si particles. 9 and 10, it can be seen that Mg ₂ Si having desired characteristics can be formed by repeatedly including a strong plastic working step and a heat treatment step.

A mixed powder of pure Mg powder and pure Si powder in a composition molar ratio of 2: 1 is made into a solidified body by the method shown in FIG. 2 (the number of BMA is 600 times), and this solidified body is pulverized using a stamp mill to obtain a powder. It was. The powder particle size is 45 μm or less.
This powder was subjected to gas spraying on a 70 mm × 150 mm × 1.6 mm thick mild steel plate by the method shown in FIG. 4 and then press-molded at a surface pressure of 800 MPa to form a coating film 19.
The obtained composite material, as shown in FIG. 11, as well as check for Mg 2 _Si peak by X-ray diffraction, as shown in FIG. 12, the cross section thereof was observed with the composite material by an optical microscope. Further, the corrosion resistance was evaluated by applying a neutral salt spray test defined in JIS Z 2371 for 100 hours. Furthermore, the hardness was measured using a Vickers hardness tester.
As a result of the X-ray diffraction, a peak of Mg ₂ Si was confirmed from the surface on which the coating was formed by gas spraying, and according to the optical microscope observation of the coating cross section, the mild steel plate and the coating were in a good bonding state, The film thickness was 50 μm (see FIG. 12).
The results of the salt spray test and hardness measurement are shown in Table 3. From the results of the salt spray test, it was confirmed that the mild steel sheet on which the Mg ₂ Si coating was formed significantly improved the corrosion resistance.

A Mg ₂ Si film was formed on the ductile cast iron plate in the same manner as in Example 4. The film thickness was 200 μm from observation with an optical microscope. Table 3 shows the results of the neutral salt spray test specified in JIS Z 2371 for 100 hours, the corrosion resistance was evaluated, and the hardness was measured using a Vickers hardness tester.

これらの結果から、いずれの実施例も、十分な厚みのＭｇ_２Ｓｉ被膜１９を有し、耐食性、硬度において優れたものであることが理解できる。An Mg ₂ Si coating was formed on an aluminum alloy (A5083) plate in the same manner as in Example 4. The film thickness was 200 μm from observation with an optical microscope.
Table 3 shows the results of the neutral salt spray test specified in JIS Z 2371 for 100 hours, the corrosion resistance was evaluated, and the hardness was measured using a Vickers hardness tester.

From these results, it can be understood that any of the Examples has a sufficiently thick Mg ₂ Si coating film 19 and is excellent in corrosion resistance and hardness.

  As described above, since the present invention is a metal material having a coating of a magnesium compound such as Si, it has excellent corrosion resistance and hardness, and can provide an excellent material such as various structures.

Claims (3)

A film forming material for providing a film deposited on the surface of a metal material,
It consists of a compound Mg ₂ X of element X selected from the group consisting of Si, Ge, Sn and Pb and magnesium (Mg), and the particle diameter of the Mg ₂ X is 10 nanometers (nm) or more and 500 nanometers ( nm) or less, a film forming material. Each starting material is weighed so that the molar ratio of magnesium (Mg) and element X selected from the group consisting of Si, Ge, Sn and Pb is Mg: X = 2: 1, and both are mixed; ,
A magnesium compound Mg having a particle diameter of 10 nanometers (nm) or more and 500 nanometers (nm) or less by subjecting the magnesium and the element X to a solid phase reaction by repeatedly applying plastic working to the mixture. ₂ synthesizing X;
Using a material comprising the magnesium compound Mg 2 _X as a film forming material, and a step of forming a magnesium compound coating consisting of Mg 2 _X by attaching the film-forming material on the surface of the metal material substrate, a metallic material Manufacturing method. The method for producing a metal material according to claim 2, wherein the metal material substrate is a substrate made of a magnesium alloy.

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